Various cables are required to use televisions (TVs), computers (PCs), and audio sets in spaces such as houses or offices. Some of generally used high definition (HD) transmission cable techniques are limited in a transfer rate and transmission capacity, which are, thus, not appropriate for processing large content at a high speed. Even an HD transmission technique, which does not support uncompressed video, lacks ability to connect video devices when these devices are away from one other by merely a few meters, and thus, a network system for smoothly providing large content services is required in a space connected by a network such as houses or offices.
In a network system supporting a specific protocol, transmission of unnecessary information in controlling a session between devices may cause an increase in network traffic. Thus, it is required to provide a session control function appropriately according to characteristics of each operating system and user convenience is required to be enhanced thereby.